Treating C8-C10 aromatic feed streams to prepare and recover trimethylated benzenes

ABSTRACT

Methods are provided for the treatment of a feed stream containing C9 aromatic components to produce mesitylene-containing products. The methods include hydrodealkylating the feed stream to remove C2 and higher alkyl groups from the aromatic components and transalkylating the feed stream to rearrange the distribution of methyl groups among the aromatic components. Disclosed methods also include the treatment of a hydrocarbon feedstock by hydrodealkylation and/or transalkylation in order to produce a hydrocarbon product having an increased mass percentage of mesitylene.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. patent application Ser. No. 15/871,678 filed Jan. 15, 2018 (7612-110), U.S. patent application Ser. No. 14/256,589 filed Apr. 18, 2014 (7612-46), U.S. Provisional Application No. 61/813,321, filed Apr. 18, 2013 (7612-31), and U.S. Provisional Application No. 61/813,333, filed Apr. 18, 2013 (7612-32), each of which is hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to the preparation of mesitylene rich fuels and blending components from heavy aromatic feeds, particularly from C9 aromatic rich streams available from refineries.

BRIEF DESCRIPTION OF THE PRIOR ART

The refining industry currently formulates the motor gasoline pool from a wide range of hydrocarbon streams including C₄ to C₁₀ saturated branched acyclic alkanes and olefins and monocyclic aromatic compounds. However derived, these latter hydrocarbon streams contain a broad range of components and have usually been distilled, or otherwise treated (e.g., by solvent extraction), to obtain specific desired components or combinations of components. One purpose of these operations in the past has been to obtain high purity, often greater than 99%, chemical feed stocks such as para-xylene and benzene, which have been used in huge quantities in the manufacture of styrene, phenol, polyamide monomers, terephthalic acid and other chemical products. The streams resulting from the separation processes accordingly consist of product streams of benzene, toluene, C₈ aromatics containing xylenes, and a bottoms product of C₉ and C₁₀+ aromatics.

There is extensive knowledge in the refining industry regarding the use of catalysts to restructure molecules for the adaptation of these C₄-C₁₀ streams. However, these techniques do not satisfy the need for high octane fuels, particularly aviation fuels for piston and turbine engines, which have unique high octane, distillation and vapor pressure requirements. The prior art primarily has focused on fuels that are not able to meet the particularly higher motor octane demands of unleaded aviation fuel (MON≥102).

For example, U.S. Pat. No. 4,172,813 describes hydrodealkylation and transalkylation of fractionated heavy reformate to produce a high yield of xylenes by use of a tungsten/molybdenum catalyst. Further, a high yield of C₂-C₄ hydrocarbons is obtained as a result of the hydrodealkylation of the alkyl aromatics. More specifically, the '813 process involves reacting the C₉'s, separating the C6, C7, C8, trimethylbenzene and C10 reaction products, and then recycling the unreacted trimethylbenzenes. The goal of the process is to convert trimethyl benzenes (“TMB”'s) to xylenes, and particularly ethylbenzene-lean xylenes, as well as benzene and C2-C4 hydrocarbons. One can make additional C8 products by transferring methyl groups from one aromatic to another, e.g., from C9's and C10's to C6's and C7's. Under the same conditions, ethyl and propyl groups can be removed, i.e., by hydrodealkylation, forming ethane, propane, etc.

All the TMB isomers have a very similar boiling point. In the '813 patent, the unreacted TMB's are recycled to be converted to lighter aromatics. See '813 patent at column 8, lines 46-51.

The present invention uses a combination of processing steps to transform a typical mixed-C9 and higher aromatic rich feed stream such as might result from catalytic reforming. Catalytic reforming is frequently followed by a BTX (benzene, toluene, xylene) unit which recovers the light aromatics by extraction, distillation, or a combination of these processes. The aromatics cut left over after the BTX process is generally a C9 and higher aromatic feedstock which can be separated into specific, high octane C9 compounds and mixtures thereof which are isolated and recovered. While some of the individual processing methods have been known in the art, they have not been combined in the manner of the present invention.

It is an object of the present invention to provide methods for the efficient and cost effective production of 1,3,5-trimethyl benzene and pseudocumene fuel products from C9 aromatic feeds. It is a further object of the invention to provide such methods which further provide lower paraffins and C6-C8 aromatics as by-products.

A further object of the present invention is to provide TMB-rich fuel products, with or without pseudocumene, as fuels and fuel blending components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic view of a C9 Stream treatment process according to the present invention.

FIG. 2 is a flow diagram showing typical major components of a process according to an embodiment of the present invention.

FIG. 3 is a flow diagram identifying further processing components, steps and products of the present invention.

FIGS. 4-16 are diagrams showing various portions of an overall process in accordance with the present invention.

SUMMARY OF THE INVENTION

This invention treats a C₉ aromatic blend feed stream to obtain a TMB-rich product. The process includes the hydrodealkylation (HDA) and transalkylation (TA) of the C9 feed to obtain the TMB-rich fraction. The process may also include further treatment to obtain a substantially pure mesitylene product and/or a mixed TMB product comprising mesitylene and pseudocumene. Recovery of other products may also be involved. The invention further comprises the TMB products of these processes. The invention thereby facilitates the preparation of an unexpectedly high octane aromatic stream, which can serve as a high-octane unleaded fuel or fuel blending component for a wide range of applications, particularly aviation gasoline and other high-performance transportation fuels. Further objects, features, aspects, benefits, advantages, and embodiments of the present invention will become apparent from the detailed description and drawings provided herewith.

DESCRIPTION OF SELECTED EMBODIMENTS

For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated herein and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications of the described embodiments, and any further applications of the principles of the invention as described herein, are contemplated as would normally occur to one skilled in the art to which the invention relates. While certain aspects of the invention are shown in detail, it will be apparent to those skilled in the relevant art that some features that are not relevant to the present invention may not be shown for the sake of clarity.

The present invention provides a surprisingly efficient and cost effective method for the production of trimethyl benzenes, and particularly 1,3,5-trimethylbenzene (mesitylene), 1,2,4-trimethylbenzene (pseudocumene) and mixtures thereof. In a preferred embodiment, mesitylene is obtained as the primary component of a mesitylene/pseudocumene blend. In another preferred embodiment, mesitylene is obtained as an essentially pure component. These products may be used in a variety of ways, particularly as motor fuels or blending components, especially for aviation fuels.

The Overall Process (FIG. 1)

The inventive process is directed to the treatment of feed streams which include C9 aromatics in combination with other components. As used herein, the term “C9 Stream” is intended to cover any available aromatic stream, including effluent refinery streams or fractions thereof, which includes a sufficient amount of C9 aromatics to make the process practical. One preferred C9 Stream is a catalytic naphtha reformer C9 effluent, particularly after BTX processing.

The C9 Stream may comprise specifically C9 aromatics, e.g., trimethyl-benzenes, ethyl-methyl-benzenes and propyl-benzenes. The stream may also comprise quantities of lower aromatics such as toluene, xylenes, ethylbenzene, etc. The C9 Stream may also include higher aromatics, such as diethylbenzenes, ethyl dimethyl benzenes, methyl propylbenzenes, tetramethylbenzenes, pentamethylbenzene and various other alkyl benzenes. Of these, the present invention is directed to the preparation and collection of mesitylene, alone or in combination with pseudocumene. This provides a C9 aromatic product which has a much increased MON compared to the initial feed stream. As exemplified hereafter, for example, the present invention can convert a C9 aromatic feed stream having a MON in the order of 100, to a C9 product having a MON of 111. The result of the present invention is therefore a product which is useful itself as a motor fuel, e.g., an aviation fuel, of high octane, and/or which may be used to blend with gasoline or other components to provide fuels of various octanes as desired.

As shown in FIG. 1, the inventive process starts with a C9 Stream which is chemically treated, alone or in combination with recycle or other feed streams. The treatments provide hydrodealkylation of ethyl, propyl and butyl groups, and transalkylation and isomerization of the C9's, to yield an effluent “A”. This process is followed by one or more steps which treat the “A” stream to allow separate collection of the desired C9 trimethylbenzene products. These further separation steps may also provide for the separate collection of xylenes, toluenes, benzene, light hydrocarbons, and hydrogen. The overall process provides a suitable yield of the desired trimethylbenzene products, as well as providing various other product streams that have value in gasolines and for other products and purposes.

C9 Aromatic Feed Streams

In the simplest form of the invention, the C9 Stream contains primarily C9 and higher components, and the process involves several steps for converting the C9 components to mesitylene and pseudocumene, particularly mesitylene. However, while a high concentration of C9 aromatics in the feed stream may be preferred, it will be appreciated that the C9 feed may also include a variety of C7-C12 components. Examples of typical feed streams are provided elsewhere herein. The present invention applies a number of processes which convert these various components of a C9 feed stream to a desirably high yield of the desired mesitylene and pseudocumene.

One process is hydrodealkylation, which selectively removes the ethyl and propyl constituents of the aromatics, while leaving the methyl constituents. A second process is isomerization, which is performed, for example, to convert 1,2,3-trimethyl benzene to the desired mesitylene and pseudocumene. Conversion to mesitylene, and/or pseudocumene, may also occur for the hydrodealkylated C9 components. Thus, a third reaction which may occur is transalkylation, which is the reaction of light (C7 and C8) and heavy methylbenzenes, i.e., C10, C11 or C12, into trimethylbenzenes, including pseudocumene and mesitylene. Optionally, saturated hydrocarbons that may be present in the feed stream will be hydrocracked into lower alkanes, which are separated by distillation.

A significant advantage of the present invention is that it is operable with aromatic feeds which are readily available, for example from catalytic reforming of heavy naphtha. A number of proprietary catalytic reforming processes are available, but they possess many features in common. The purpose of catalytic reforming is to increase the octane number of a refinery stream, primarily by converting the naphthenes to aromatics and the paraffins to more branched structures. Typically feed stocks are rich in paraffins and naphthenes with some aromatic content and product streams are somewhat reduced in paraffin content, but significantly reduced in naphthenes. Aromatics are usually the largest component of catalytic reformate. Depending on the refinery and the feed stocks available, different degrees of reaction severity may be chosen. In general the higher the severity, the higher the aromatic content and the lower the paraffin content of the effluent.

Although catalytic reforming is a net hydrogen producer, some hydrogen is typically recycled to the feed to help minimize coking. Reactors are typically fixed bed units. The net reaction is endothermic. Heat is supplied by a process furnace. There may be multiple passes through the furnace and multiple separate catalyst beds.

Although catalytic reforming processes differ in the catalyst formulations used, all current processes use precious Pt group metals. Because precious metal catalysts are subject to poisoning, feed to catalytic reforming is typically treated to remove sulfur compounds and other catalyst poisons. Operation may be described as continuous, cyclic or regenerative; these terms are descriptive of equipment configurations designed to permit replacement and/or regeneration of catalyst without complete unit shutdown. This is an important consideration because reforming catalysts tend to become fouled over time by the deposition of coke, although they can be regenerated by oxidation. A fuller discussion of catalytic reforming can be found in Antos, G. J. and Aitani, A. M., “Catalytic Naphtha Reforming” Marcel Dekker. (2004) and Rahimpour, M. R. et al., Applied Energy, v109, pages 79-93 (2013) “Progress in Catalytic Naphtha Reforming Process: A Review”.

Such feeds are the result of the typical naphtha reformate process, for example, and may include a variety of other aromatic components, as well as non-aromatic components such as alkanes. Typical refinery C9 fractions may include a variety of C7-C10 components. For example, heavy reformate typically contains significant amounts of C10 and higher aromatics. Heavy reformate may be treated by distillation to remove the C10's and heavier components, yielding “fractionated heavy reformate.” Benzene, toluenes and xylenes may be removed through a conventional BTX process, which sometimes has already been carried out by the refinery before the C9 fraction is isolated. The concentration of C9 aromatics in the feed will depend on the processing of the feed prior to its use in the present invention.

It is a significant advantage of the present invention that the process uniquely combines several types of treatments which effectively eliminate or convert these various feed streams to the desired C9 product(s) in high proportion.

Table 1 lists typical constituents of a heavy reformate feed useful with the present invention.

TABLE 1 Composition of heavy reformate feedstock. Major compound Short name wt. % Iso-propyl benzene iPB 1.7 n-Propyl benzene nPB 4.3 1-Methyl 2-ethyl benzene 1M2EB 6.5 1-Methyl 3-ethyl benzene 1M3EB 18.5 1-Methyl 4-ethyl benzene 1M4EB 9.1 1,2,3-Tri-methyl benzene 123TMB 6.6 1,2,4-Tri-methyl benzene 124TMB 39.1 1,3,5-Tri-methyl benzene 135TMB 10.1 Total A₉ 95.9 n-Butyl benzene nBB 0.5 1,4-Diethyl benzene 14DEB 0.8 1,3-Diethyl benzene 13DEB 0.4 1,3-Dimethyl, 5-ethyl benzene 13DM5EB 0.8 1,4-Dimethyl, 2-ethyl benzene 14DM2EB 0.4 Others A₁₀ 1.2 Total A₁₀ 4.1

Process Components

HDA

The present invention includes the steps of aromatic hydrodealkylation (HDA) of certain aromatic compounds that may be present in the C9 aromatic feed. The process is carried out under conditions which do not cleave the substituent methyl groups, but will selectively remove the higher C2-C4 alkyl substituents, as their corresponding alkanes, thus converting the higher (C2+) alkyl benzenes to leave only a mix of benzene and methylated benzenes as the aromatic constituents. For example, ethyl toluene is converted to ethane and toluene, propyl benzene is converted to propane and benzene, and butyl benzene (a C10 compound) is converted to butane and benzene. The consequence of the HDA process is therefore the production of, inter alia, benzene, toluene and polymethyl benzenes, including xylenes, as well as certain lower alkanes.

TA

The transalkylation (TA) and isomerization step results in a redistribution of methyl groups among the aromatics. Any of the C6-C10 aromatics may be affected by TA. Thus, a C8 aromatic may add a methyl group or a C10 may give up a methyl group—each resulting in formation of a TMB. The present invention combines HDA and TA with correlated recycle and recovery steps to obtain a high yield of mesitylene.

One aspect of this process, therefore, involves taking advantage of the known equilibrium distribution of trimethyl benzenes in an aromatic pool. Egan describes aspects of the equilibrium distribution of methylbenzenes in transalkylation. See Egan, Clark J., “Calculated Equilibria of the Methylbenzenes and Benzene from 298° to 1000° K”, J. Chem. And Eng. Data 5 (3) 298, July 1960, hereby incorporated by reference in its entirety. The present process includes selectively recovering the mesitylene, by itself or optionally with the pseudocumene, from the equilibrium pool of the C9 and other isomers.

As known in the art, a relevant parameter in transalkylation is the ratio in the feed stream of methyl groups to benzene groups. Egan shows, for example, that the equilibrium mesitylene concentration (as well as the pseudocumene concentration) peaks at a methyl/benzene ratio of 3.0. It is therefore a preferred embodiment of the present invention, though not a requirement, to operate the transalkylation step with a methyl/benzene ratio of the feed close to 3.0. This is readily accomplished, for example, by recycling tetra and higher methylbenzenes. Note that these higher alkylbenzenes need only be present at the final transalkylation step and need not flow through the multi-stage hydrodealkylation system.

Sample HDA/TA Processes

The HDA/TA process is generally understood in the art. It provides for the removal of C2 and higher alkyl groups from the aromatics of the C9 Stream, and an equilibrium distribution of the methyl groups among the aromatics. An example of a conventional combined HDA/TA process is described in detail in U.S. Pat. No. 4,172,813, which is hereby incorporated by reference in its entirety. As described in the '813 patent, for example, the feed is contacted with a suitable catalyst in the presence of a hydrogen-affording gas. The '813 patent describes a TMB stream which is an equilibrium mixture of C9 methyl aromatics with essentially all higher alkyl groups removed. The feed stock contained 65% toluene with the balance C9 and higher aromatics. Close to equilibrium results are obtained at 800-900° F. and 172 PSIG at a WHSV of 3.7 or 3.8 hr⁻¹. Excess hydrogen for the dealkylation reaction was provided; the examples use just over 6:1 of H2:hydrocarbon. Various operating conditions are selected to suit the catalyst, which may include particular molar ratios of hydrogen to hydrocarbon, not including inert, gas phase hydrocarbons. Operating pressures, temperatures and contact times are also selected in accordance with known operation of these types of catalysts.

Catalysts

An example of a suitable catalyst is a metal and zeolite operated at temperatures from 200-1000° C., pressures from 1-100 atmospheres and a space velocity from 0.1-10 hr⁻¹. The catalyst metals include, Pt, Pd, Re, Rh, Ir and Mo. These may be present as an oxide, metallic or alloy nano-particles. The preferred metals are Pt, Re and Mo. The metal loadings can be from 0.05 to about 10 weight % as metal in the catalyst. The metals are typically supported on a high surface area support such as alumina, silica, and other refractory oxides. These oxides provide high surface area, porosity and physical strength. The oxide support also contains an acidic form of zeolite Y (FAU), beta (BEA), mordenite (MOR), ZSM-5 (MFI). The amount of zeolite may be from about 10% to 90% of the oxide support. For C9 aromatic feeds, large pore zeolites are preferred, including zeolite Y (FAU), mordenite (MOR) and beta (BEA).

The combined process of HDA and TA thus treats the C9 components in a manner to increase the proportion of desired mesitylene and pseudocumene, while converting other likely present components to readily eliminated compounds. Hemimellitene, 1,2,3, trimethylbenzene, is the most difficult component to separate by distillation from mesitylene and pseudocumene. Fortunately, as shown by Egan, the equilibrium concentration of hemimellitene is always quite low. The ethyl toluenes which have a boiling point close to that of mesitylene are eliminated by removing the ethyl groups in the HDA process. Unlike ethyl toluenes, the boiling point of toluene is sufficiently different that it is readily separated from mesitylene (and pseudocumene) by distillation. As a result, all components present following the HDA/TA processes are readily separated from the mesitylene and pseudocumene. For example, the benzene, toluenes and xylenes, if not converted to the desired trimethyl benzenes, can be removed through a conventional BTX tower. The lower alkanes and hydrogen are easily separated in a conventional manner prior to the BTX tower, and could even be removed prior to the TA unit when operated separately from the HDA reactors.

Hydrocracking

As has been previously described, many refineries practice high severity catalytic reforming and follow this operation with what is known in the art as a BTX extraction unit to recover the light aromatics valuable as chemical feed stocks. In this scenario, the reformer effluent contains a relatively low concentration of light paraffins which are conveniently removed prior to the BTX unit. BTX raffinate is heavy aromatics suitable for feed to the present invention.

If a significant amount of paraffins are present in the C9 Stream, the process preferably includes the step of hydrocracking. Hydrocracking is well known in the art and occurs under the same reactions conditions as HDA and TA. Alkanes and cycloalkanes are cracked into lower molecular weight alkanes, which are separated by distillation.

BTX

Table 2 provides a typical effluent composition from a low severity catalytic reformer. This stream may be fed directly into the process of the present invention. The paraffin components will pass through both the HDA and TA reactors unreacted. Transalkylation effluent can then conveniently be fed to a BTX unit whose raffinate will be a mixture of C9 and higher methyl aromatics. A pseudocumene/mesitylene mixture is readily recovered from this stream (and can be further processed to obtain pure mesitylene), leaving a higher aromatics stream suitable for recycle to transalkylation.

TABLE 2 C5 paraffin 0.272 C6 paraffin 0.04 C7 paraffin 0.041 C8 paraffin 0.053 C9 paraffin 0.033 C10 paraffin 0.007 Naphthenes 0.01 Benzene 0.009 Toluene 0.136 C8 aromatics 0.274 C9 aromatics 0.126 Total 1.001

Alternatively, if the hydrodealkylation and transalkylation reactions are carried out in separate reactors, the BTX unit can be positioned between the HDA and TA steps. In this case, a simple BTX distillation can remove C6-C8 components formed in TA. As above, a pseudocumene/mesitylene mixture can be recovered by distillation and the heavier aromatics can be recycled.

Many commercial proprietary BTX extraction systems are available and are known by trade names such as Udex and Tetra. Solvents such as higher ethylene or propylene glycols or sulfolane are employed. Any of these systems are suitable for use as above described.

The Process in Detail (FIGS. 2-3)

The present invention is shown diagrammatically in FIG. 1. This diagram indicates the overall process involving the HDA and TA processes, combined with recycle of certain components, which increase the concentration of mesitylene over that present in the initial C9 Stream. This process generally involves several conventional steps which are combined in a unique manner, with other process methodology, to produce a product which is rich in TMB. A more specific exemplary process is described hereafter, but it will be appreciated that certain aspects of the described process may be varied as understood by those skilled in the art. For example, the following description provides separate HDA and TA reactors, but it is within the skill in the art to operate such reactors so as to achieve concurrent HDA and TA within individual reactors.

Referring to FIG. 2, there is shown a preferred embodiment of a process 10 according to the present invention. In general, the feed stock is treated using one or more adiabatic reactors operating at conditions to perform the HDA/TA processes, as generally known. The use of multiple reactors, with intermediate heat removal to steam, facilitates control of the exothermic HDA reactions. HDA can also be carried out in an isothermal reactor wherein the catalyst is contained in tubes and a heat transfer fluid on the shell side removes the heat. Typical heat transfer fluids are Dowtherm and other heat transfer oils or high pressure steam. It is also well known in the art to place the catalyst on the shell side of an isothermal reactor and the heat transfer fluid in the tubes. Cold shot cooling can also be employed. In this embodiment, instead of recovering the heat to steam in between reactor stages, additional cold hydrogen or other inert gas or liquid component is added between stages.

Typically, the C9 Stream is mixed with a hydrogen-containing gas and preheated to a suitable temperature, and then transferred to the hydrodealkylation/transalkylation reaction zone. Besides being a reactant, the hydrogen also provides dilution of the hydrocarbon stream and limits the adiabatic temperature rise across each reaction stage. It will be clear to one of skill in the art that the hydrogen can be replaced in part (only in part because the hydrogen is reactant as well as diluent) by a gas inert in the reaction such as nitrogen or a lower hydrocarbon such as methane, ethane or propane or mixtures thereof or mixtures thereof further comprising hydrogen or nitrogen. As shown in FIG. 2, the C9 Stream 11 is provided to booster pump 12 which elevates the liquid to a reaction pressure, e.g., 400 PSIA, before the stream enters vaporization furnace 13. Hydrogen recycle 14 is combined with make-up hydrogen 15 and passes through a separate coil in furnace 13. These gas phase streams combine before entering the first stage reactor 16. Effluent 17 enters a waste heat boiler 18 where it is cooled by generating 750 PSI steam 19. A second stage reactor 20 and boiler 21 are preferably included, and one or more additional stages (not shown) may be added. In this embodiment, effluent from the last of the HDA stages is mixed with a C9 and higher aromatics recycle stream 22 (from a subsequent separation section) before being fed to a transalkylation reactor 23, which yields effluent stream 24.

As shown in FIG. 3, the effluent 24 from the HDA/TA reactor(s) is fed to a quench column 25 which cools the material. This cooled material is then fed through line 26 to a partial condensation unit 27. The lighter components comprising C2-C4 paraffins and hydrogen are removed by way of line 28 and the heavier components comprising C6-C10 and higher aromatics are removed through line 29. Alternatively, the quench column overheads can be fed to an absorption or extraction unit to separate the hydrogen from the light hydrocarbons. The heavier components in line 29 are then fed into a conventional type BTX (benzene/toluene/xylene) column 30. The BTX column separates out the toluenes, xylenes, and benzene (31) from the C9 and higher aromatics.

The bottoms 32 from the BTX column pass to the product column 33 which takes the desired mesitylene/pseudocumene product overhead 34 from a bottoms including some pseudocumene and higher polymethylbenzenes. Pseudocumene distributes between the overheads and bottoms of this column. A purge 35 of C10 and higher aromatics is taken form the bottoms of this column to prevent unreactive heavy compounds from building up. The balance 36 of the higher polymethylbenzenes is recycled to the transalkylation unit by way of line 22 (FIG. 2).

The lighter component overheads 28 from quench column 27 may also be processed for recovery of the lighter components. Most of the C₃ and C₄ is removed against cooling water and the residual gasses pass to an ethane chiller (not shown) where the ethane is condensed against chilled brine at about −5° C. Uncondensed hydrogen is recompressed to reaction pressure and recycled through line 14 (FIG. 2).

This process yields a TMB-rich product containing primarily mesitylene (1,3,5-trimethyl benzene), and some amount of pseudocumene. As used herein, the term “TMB-rich” refers to a C9 aromatic product containing at least about 50 wt % mesitylene, preferably at least 60 wt % mesitylene and more preferably at least 70 wt % mesitylene. The TMB-rich product is well suited for use as a motor fuel, especially an aviation fuel, either as it is obtained or after blending with other components. In particular, the presence of the mesitylene provides a desirably high MON and other characteristics suitable for such fuels. It is an additional advantage of the present invention that the inventive process provides TMB-rich products which have this utility in the absence of TEL and aromatic amines.

The process may optionally include a further purification of the TMB-rich product to obtain a Substantially Pure Mesitylene product, which refers to a product that is at least about 90 wt % mesitylene, and preferably at least 95 wt % mesitylene. To obtain a Substantially Pure Mesitylene product, an additional column is used to resolve the pseudocumene and mesitylene. In one approach, for example, a column is included which is used to take an overhead pseudocumene composition as 98 wt %. However, it will be found that in most instances the TMB-rich product is sufficient and has excellent utility as a fuel or fuel blending component, without requiring the additional steps required to obtain a Substantially Pure Mesitylene product.

Auxiliary equipment, such as pumps and heat exchangers, are not shown in the drawings. Such auxiliary equipment is well-known and the uses and locations of this equipment in this process system will be recognized easily by those having ordinary skill in the art.

Mention Combining of HDA and TA.

Further embodiments and aspects of the process of the present invention may be found in the following examples. These embodiments and examples are presented for purposes of illustration only and are not intended to limit the scope of the invention.

Example 1

The present invention is useful with a variety of C9 aromatic streams, including those obtained directly from a reformer. By way of example, a C9 stream from catalytic reforming was analyzed for chemical composition and was found to contain the components as set forth in Table 2.

TABLE 3 Reformate Sample (C₈, C₉ & C₁₀ Aromatic Stream) 95-63-6 1,2,4-trimethyl-benzene 38.174% 611-14-3 1-ethyl-2-methyl-benzene 17.316% 622-96-8 1-ethyl-4-methyl-benzene 8.537% 526-73-8 1,2,3-trimethyl-benzene 7.280% 108-67-8 1,3,5-trimethyl-benzene 5.520% 108-38-3 1,3-dimethyl-benzene 3.097% 141-93-5 1,3-diethyl-benzene 2.779% 873-49-4 cyclopropyl-benzene 2.088% 2870-04-4 2-ethyl-1,3-dimethyl-benzene 2.036% 1074-43-7 1-methyl-3-propyl-benzene 1.561% 933-98-2 1-ethyl-2,3-dimethyl-benzene 1.230% 95-93-2 1,2,4,5-tetramethyl-benzene 1.050% 874-41-9 1-ethyl-2,4-dimethyl-benzene 1.011% 103-65-1 propyl-benzene 0.915% 95-93-2 1,2,4,5-tetramethyl-benzene 0.715% 535-77-3 m-Cymene 0.697% 135-98-8 S-Butyl-benzene 0.657% 488-23-3 1,2,3,4-tetramethyl-benzene 0.479% 934-80-5 4-ethyl-1,2-dimethyl-benzene 0.396% 106-42-3 P-Xylene 0.319% 91-20-3 Napthalene 0.267% 135-98-8 S-Butyl-benzene 0.250% 104-51-8 butyl-benzene 0.224% 2870-04-4 2-ethyl-1,3-dimethyl-benzene 0.201% 135-01-3 1,2-diethyl-benzene 0.162% 768-49-0 (2-methyl-1-propenyl)-benzene 0.149% Unknown 2.890% 100.000%

After processing in accordance with the present invention, including hydrodealkylation and transalkylation/isomerization, the resulting mixture of tri-methyl C9-aromatics produces products as shown in Table 3. Table 3 highlights specifically how this invention separates the various compounds via hydrodealkylation of the ethyl and propyl groups resulting in ethane, propane, benzene, toluene and xylene, and isomerization of the methyl benzenes, yielding the trimethyl benzenes. Referring to Table 3, it is shown, for example, that 1-ethyl-2-methyl-benzene yields ethane and toluene, and 1,3-diethyl-benzene is broken down to ethane and benzene.

TABLE 4 DEALKYLATION SNYTHESIS -- FOR DISTILLATION C₂H₆ C₃H₈ n-C₄H₁₀ i-C₄H₁₀ C₆C₆ C₇H₈ C₈H₁₀ Ethane Propane Butane Isobutane Benzene Toluene Xylene X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X −89° C. −42° C. −1° C. −9° C. 80° C. 111° C. 135° C. Typical Boiling Points Reformate Sample (C₈, C₉ & C₁₀ Aromatic Stream)  95-63-6 1,2,4-trimethyl-benzene 38.174%  611-14-3 1-ethyl-2-methyl-benzene 17.316%  622-96-8 1-ethyl-4-methyl-benzene 8.537% 526-73-8 1,2,3-trimethyl-benzene 7.280% 108-67-8 1,3,5-trimethyl-benzene 5.520% 108-38-3 1,3-dimethyl-benzene 3.097% 141-93-5 1,3-diethyl-benzene 2.779% 873-49-4 cyclopropyl-benzene 2.088% 2870-04-4  2-ethyl-1,3-dimethyl-benzene 2.036% 1074-43-7  1-methyl-3-propyl-benzene 1.561% 933-98-2 1-ethyl-2,3-dimethyl-benzene 1.230%  95-93-2 1,2,4,5-tetramethyl-benzene 1.050% 874-41-9 1-ethyl-2,4-dimethyl-benzene 1.011% 103-65-1 propyl-benzene 0.915%  95-93-2 1,2,4,5-tetramethyl-benzene 0.715% 536-77-3 m-Cymene 0.697% 135-77-3 S-Butyl-benzene 0.657% 488-23-3 1,2,3,4-tetramethyl-benzene 0.479% 934-80-5 4-ethyl-1,2-dimethyl-benzene 0.396% 106-42-3 P-Xylene 0.319%  91-20-3 Napthalene 0.267% 135-98-8 S-Butyl-benzene 0.250% 104-51-8 butyl-benzene 0.224% 2870-04-4  2-ethyl-1,3-dimethyl-benzene 0.201% 135-01-3 1,2-diethyl-benzene 0.162% 768-49-0 (2-methyl-1-propenyl)-benzene 0.149% Unknown 2.890% 100.000% 

Following processing in accordance with the present invention, an initial feed is converted as follows (based on vol %):

TABLE 5 Prior to Processing After Processing Mesitylene 7.37% 24.61% Pseudocumene 37.52% 11.94% Mixed C9's/C10's+ 50.60% 9.62% Mixed-Xylenes 4.51% 38.71% Toluene 0 6.75%

By way of further example, a heat and material balance has been prepared based on a typical C8-C10 feed stream. Referring to FIG. 4, there is shown the initial feed and preliminary processing thereof for passing the feed to the system. This composition of the feed is shown in the following table as Stream Number 1:

STREAM NUMBER 1 2 TEMPERATURE DEG F. 77 82 PRESSURE PSIA 15 405 COMPONENTS HYDROGEN LB/HR 0 0 METHANE LB/HR 0 0 WATER LB/HR 0 0 ETHANE LB/HR 0 0 PROPANE LB/HR 0 0 BUTANE LB/HR 0 0 TOLUENE LB/HR 0 0 BENZENE LB/HR 0 0 O_XYLENE LB/HR 0 0 _124TRIMETHYLBENZENE LB/HR 23,827 23,827 _1ETHYL2METHYLBENZENE LB/HR 10,808 10,808 _1ETHYL4METHYLBENZENE LB/HR 5,328 5,328 _123TRIMETHYLBENZENE LB/HR 4,544 4,544 _135TRIMETHYLBENZENE LB/HR 3,445 3,445 M_XYLENE LB/HR 1,707 1,707 _13DIETHYLBENZENE LB/HR 3,392 3,392 _2ETHYL13DIMETHYLBENZENE LB/HR 1,559 1,559 _1METHYL3PROPYLBENZENE LB/HR 1,088 1,088 _1ETHYL23DIMETHYLBENZENE LB/HR 857 857 _124STETRAMETHYLBENZENE LB/HR 1,230 1,230 _1ETHYL24DIMETHYLBENZENE LB/HR 705 705 PROPYLBENZENE LB/HR 571 571 M_CYMENE LB/HR 486 486 SEC_BUTYLBENZENE LB/HR 632 632 _1234TETRAMETHYLBENZENE LB/HR 334 334 _4ETHYL12DIMETHYLBENZENE LB/HR 276 276 P_XYLENE LB/HR 176 176 NAPTHALENE LB/HR 247 247 BUTYLBENZENE LB/HR 156 156 _12DIETHYLBENZENE LB/HR 113 113 _2METHYL1PROPYLBENZENE LB/HR 102 102 _123STETRAMETHYLBENZENE LB/HR 0 0 PENTAMETHYLBENZENE LB/HR 0 0 BICYCLOHEXYL LB/HR 2,496 2,496 TOTAL LB/HR 64,080 64,080 ENTHALPY BTU/LB −224 −222 DENSITY LB/CUFT 54.51 54.36 VOLUMETRIC FLOW GPM 147 147

The entire system is shown diagrammatically in FIGS. 4-16. The compositions of the various streams are shown in the following tables.

STREAM NUMBER 2 3 4 5 19 30 38 TEMPERATURE DEG F. 82 111 339 761 392 350 148 PRESSURE PSIA 405 405 405 400 330 330 405 COMPONENTS HYDROGEN LB/HR 0 6,281 6,281 6,281 5,806 5,806 6,281 METHANE LB/HR 0 0 0 0 0 0 0 WATER LB/HR 0 0 0 0 0 0 0 ETHANE LB/HR 0 1,037 1,037 1,037 7,406 7,406 1,037 PROPANE LB/HR 0 0 0 0 761 761 0 BUTANE LB/HR 0 0 0 0 341 341 0 TOLUENE LB/HR 0 0 0 0 4,509 4,509 0 BENZENE LB/HR 0 0 0 0 0 0 0 O_XYLENE LB/HR 0 0 0 0 5,474 5,474 0 _124TRIMETHYLBENZENE LB/HR 23,827 23,827 23,827 23,827 31,467 31,467 0 _1ETHYL2METHYL- LB/HR 10,808 10,808 10,808 10,808 0 0 0 BENZENE _1ETHYL4METHYL- LB/HR 5,328 5,328 5,328 5,328 0 0 0 BENZENE _123TRIMETHYLBENZENE LB/HR 4,544 4,544 4,544 4,544 1,666 1,666 0 _135TRIMETHYLBENZENE LB/HR 3,445 3,445 3,445 3,445 14,435 14,435 0 M_XYLENE LB/HR 1,707 1,707 1,707 1,707 14,641 14,641 0 _13DIETHYLBENZENE LB/HR 3,392 3,392 3,392 3,392 0 0 0 _2ETHYL13DIMETHYL- LB/HR 1,559 1,559 1,559 1,559 0 0 0 BENZENE _1METHYL3PROPYL- LB/HR 1,088 1,088 1,088 1,088 0 0 0 BENZENE _1ETHYL23DIMETHYL- LB/HR 857 857 857 857 0 0 0 BENZENE _1245TETRAMETHYL- LB/HR 1,230 1,230 1,230 1,230 19,532 19,532 0 BENZENE _1ETHYL24DIMETHYL- LB/HR 705 705 705 705 0 0 0 BENZENE PROPYLBENZENE LB/HR 571 571 571 571 0 0 0 M_CYMENE LB/HR 486 486 486 486 0 0 0 SEC_BUTYLBENZENE LB/HR 632 632 632 632 0 0 0 _1234TETRAMETHYL- LB/HR 334 334 334 334 445 445 0 BENZENE _4ETHYL12DIMETHYL- LB/HR 276 276 276 276 0 0 0 BENZENE P_XYLENE LB/HR 176 176 176 176 5,590 5,590 0 NAPTHALENE LB/HR 247 247 247 247 0 0 0 BUTYLBENZENE LB/HR 156 156 156 156 0 0 0 _12DIETHYLBENZENE LB/HR 113 113 113 113 0 0 0 _2METHYL1PROPYL- LB/HR 102 102 102 102 0 0 0 BENZENE _1235TETRAMETHYL- LB/HR 0 0 0 0 5,767 5,767 0 BENZENE PENTAMETHYLBENZENE LB/HR 0 0 0 0 1,986 1,986 0 BICYCLOHEXYL LB/HR 2,496 2,496 2,496 2,496 0 0 0 TOTAL LB/HR 64,080 71,398 71,398 71,398 119,825 119,825 7,318 ENTHALPY BTU/LB −222 −195 5 431 56 −63 42 DENSITY LB/CUFT 54.36 1.46 1.02 0.59 1.07 1.33 0.14 VOLUMETRIC_FLOW GPM 147 6,080 8,757 14,983 113,955 11,253 6,321 STREAM NUMBER 5 6 7 8 9 10 11 TEMPERATURE DEG F. 761 932 751 932 761 932 392 PRESSURE PSIA 400 390 380 370 360 350 340 COMPONENTS MW HYDROGEN 6,281 6,123 6,123 5,910 5,910 5,806 5,806 METHANE 0 0 0 0 0 0 0 WATER 0 0 0 0 0 0 0 ETHANE 1,037 3,160 3,160 6,005 6,005 7,406 7,406 PROPANE 0 254 254 593 593 761 761 BUTANE 0 114 114 266 266 341 341 TOLUENE 0 4,507 4,507 10,547 10,547 13,522 13,522 BENZENE 0 957 957 2,239 2,239 2,870 2,870 O_XYLENE 0 299 299 699 699 896 896 _124TRIMETHYLBENZENE 23,827 23,827 23,827 23,827 23,827 23,827 23,827 _1ETHYL2METHYL- 10,808 7,205 7,205 2,378 2,378 0 0 BENZENE _1ETHYL4METHYL- 5,328 3,552 3,552 1,172 1,172 0 0 BENZENE _123TRIMETHYLBENZENE 4,544 4,544 4,544 4,544 4,544 4,544 4,544 _135TRIMETHYLBENZENE 3,445 3,445 3,445 3,445 3,445 3,445 3,445 M_XYLENE 1,707 2,304 2,304 3,104 3,104 3,498 3,498 _13DIETHYLBENZENE 3,392 2,262 2,262 746 746 0 0 _2ETHYL13DIMETHYL- 1,559 1,040 1,040 343 343 0 0 BENZENE _1METHYL3PROPYL- 1,088 725 725 239 239 0 0 BENZENE _1ETHYL23DIMETHYL- 857 572 572 189 189 0 0 BENZENE _1245TETRAMETHYL- 1,230 1,230 1,230 1,230 1,230 1,230 1,230 BENZENE _1ETHYL24DIMETHYL- 705 470 470 155 155 0 0 BENZENE PROPYLBENZENE 571 381 381 126 126 0 0 M_CYMENE 486 324 324 107 107 0 0 SEC_BUTYLBENZENE 632 421 421 139 139 0 0 _1234TETRAMETHYL- 334 334 334 334 334 334 334 BENZENE _4ETHYL12DIMETHYL- 276 184 184 61 61 0 0 BENZENE P_XYLENE 176 176 176 176 176 176 176 NAPTHALENE 242 247 247 247 247 247 247 BUTYLBENZENE 156 104 104 34 34 0 0 _12DIETHYLBENZENE 113 75 75 25 25 0 0 _2METHYL1PROPYL- 102 68 68 23 23 0 0 BENZENE _1235TETRAMETHYL- 0 0 0 0 0 0 0 BENZENE PENTAMETHYLBENZENE 0 0 0 0 0 0 0 BICYCLOHEXYL 2,496 2,496 2,496 2,496 2,496 2,496 2,496 TOTAL LB/HR 71,398 71,398 71,398 71,398 71,398 71,398 71,398 ENTHALPY BTU/LB 431 560 412 534 386 520 65 DENSITY LB/CUFT 0.59 0.51 0.56 0.48 0.53 0.46 0.74 VOLUMETRIC_FLOW GPM 14,983 17,518 15,770 18,463 16,645 19,517 12,001 STREAM NUMBER 11 12 19 41 TEMPERATURE DEG F. 392 392 392 392 PRESSURE PSIA 340 340 330 340 COMPONENTS MW HYDROGEN 5,806 5,806 5,806 0 METHANE 0 0 0 0 WATER 0 0 0 0 ETHANE 7,406 7,406 7,406 0 PROPANE 761 761 761 0 BUTANE 341 341 341 0 TOLUENE 13,522 13,522 4,509 0 BENZENE 2,870 2,870 0 0 O_XYLENE 896 896 5,474 0 _124TRIMETHYLBENZENE 23,827 45,691 31,467 21,865 _1ETHYL2METHYL- 0 0 0 0 BENZENE _1ETHYL4METHYL- 0 0 0 0 BENZENE _123TRIMETHYLBENZENE 4,544 6,040 1,666 1,497 _135TRIMETHYLBENZENE 3,445 3,561 14,435 115 M_XYLENE 3,498 3,498 14,641 0 _13DIETHYLBENZENE 0 0 0 0 _2ETHYL13DIMETHYL- 0 0 0 0 BENZENE _1METHYL3PROPYL- 0 0 0 0 BENZENE _1ETHYL23DIMETHYL- 0 0 0 0 BENZENE _1245TETRAMETHYL- 1,230 18,803 19,532 17,573 BENZENE _1ETHYL24DIMETHYL- 0 0 0 0 BENZENE PROPYLBENZENE 0 0 0 0 M_CYMENE 0 0 0 0 SEC_BUTYLBENZENE 0 0 0 0 _1234TETRAMETHYL- 334 734 445 400 BENZENE _4ETHYL12DIMETHYL- 0 0 0 0 BENZENE P_XYLENE 176 176 5,590 0 NAPTHALENE 247 247 0 0 BUTYLBENZENE 0 0 0 0 _12DIETHYLBENZENE 0 0 0 0 _2METHYL1PROPYL- 0 0 0 0 BENZENE _1235TETRAMETHYL- 0 5,189 5,767 5,189 BENZENE PENTAMETHYLBENZENE 0 1,787 1,986 1,787 BICYCLOHEXYL 2,496 2,496 0 0 TOTAL LB/HR 71,398 119,825 119,825 48,427 ENTHALPY BTU/LB 63 −6 56 −111 DENSITY LB/CUFT 0.74 1.24 1.07 45.27 VOLUMETRIC_FLOW GPM 12,001 12,063 13,955 133 STREAM NUMBER 30 45 46 47 48 51 70 74 TEMPERATURE DEG F. 350 200 200 150 101 159 100 200 PRESSURE PSIA 330 335 335 330 320 321 330 340 COMPONENTS MW HYDROGEN 5,806 5,803 3 3 3,803 3 3 5,806 METHANE 0 0 0 0 0 0 0 0 WATER 0 0 0 0 0 0 0 0 ETHANE 7,406 7,067 339 339 6,914 492 339 7,406 PROPANE 761 654 107 107 574 187 107 761 BUTANE 341 230 112 112 71 270 112 341 TOLUENE 4,509 389 4,120 4,120 48 4,461 4,120 4,509 BENZENE 0 0 0 0 0 0 0 0 O_XYLENE 5,474 168 5,306 5,306 15 5,459 5,306 5,474 _124TRIMETHYLBENZENE 31,467 425 31,042 31,042 31 31,436 31,042 31,467 _1ETHYL2METHYL- 0 0 0 0 0 0 0 0 BENZENE _1ETHYL4METHYL- 0 0 0 0 0 0 0 0 BENZENE _123TRIMETHYLBENZENE 1,666 18 1,648 1,648 1 1,664 1,648 1,666 _135TRIMETHYLBENZENE 14,435 217 14,218 14,218 16 14,420 14,218 14,435 M_XYLENE 14,641 539 14,102 14,102 52 14,589 14,102 14,641 _13DIETHYLBENZENE 0 0 0 0 0 0 0 0 _2ETHYL13DIMETHYL- 0 0 0 0 0 0 0 0 BENZENE _1METHYL3PROPYL- 0 0 0 0 0 0 0 0 BENZENE _1ETHYL23DIMETHYL- 0 0 0 0 0 0 0 0 BENZENE _1245TETRAMETHYL- 19,532 102 19,430 19,430 0 19,526 19,430 19,532 BENZENE _1ETHYL24DIMETHYL- 0 0 0 0 0 0 0 0 BENZENE PROPYLBENZENE 0 0 0 0 0 0 0 0 M_CYMENE 0 0 0 0 0 0 0 0 SEC_BUTYLBENZENE 0 0 0 0 0 0 0 0 _1234TETRAMETHYL- 445 2 443 443 0 445 443 445 BENZENE _4ETHYL12DIMETHYL- 0 0 0 0 0 0 0 0 BENZENE P_XYLENE 5,590 210 5,380 5,380 20 5,569 5,380 5,590 NAPTHALENE 0 0 0 0 0 0 0 0 BUTYLBENZENE 0 0 0 0 0 0 0 0 _12DIETHYLBENZENE 0 0 0 0 0 0 0 0 _2METHYL1PROPYL- 0 0 0 0 0 0 0 0 BENZENE _1235TETRAMETHYL- 5,767 28 5,738 5,738 1 5,765 5,738 5,767 BENZENE PENTAMETHYLBENZENE 1,986 3 1,983 1,983 0 1,986 1,983 1,986 BICYCLOHEXYL 0 0 0 0 0 0 0 0 TOTAL LB/HR 119,825 15,856 103,969 103,969 13,553 106,272 103,969 119,825 ENTHALPY BTU/LB −63 −396 −158 −182 −618 −179 −203 −190 DENSITY LB/CUFT 1.33 0.24 50.49 52.01 0.23 51.57 53.47 1.77 VOLUMETRIC_FLOW GPM 11,253 8,303 257 249 7,326 257 242 8,438 STREAM NUMBER 14 15 16 20 26 27 41 51 TEMPERATURE DEG F. 95 376 95 331 401 401 392 159 PRESSURE PSIA 15 21 15 15 340 340 340 321 COMPONENTS MW HYDROGEN 0 0 3 0 0 0 0 3 METHANE 0 0 0 0 0 0 0 0 WATER 0 0 0 0 0 0 0 0 ETHANE 137 0 355 0 0 0 0 492 PROPANE 116 0 71 0 0 0 0 187 BUTANE 232 0 38 0 0 0 0 270 TOLUENE 4,446 0 15 0 0 0 0 4,461 BENZENE 0 0 0 0 0 0 0 0 O_XYLENE 5,364 92 4 92 0 0 0 5,459 _124TRIMETHYLBENZENE 0 31,436 0 7,142 2,429 21,865 21,865 31,436 _1ETHYL2METHYL- 0 0 0 0 0 0 0 0 BENZENE _1ETHYL4METHYL- 0 0 0 0 0 0 0 0 BENZENE _123TRIMETHYLBENZENE 0 1,664 0 2 166 1,497 1,497 1,664 _135TRIMETHYLBENZENE 0 14,420 0 14,291 13 115 115 14,420 M_XYLENE 14,573 1 15 1 0 0 0 14,589 _13DIETHYLBENZENE 0 0 0 0 0 0 0 0 _2ETHYL13DIMETHYL- 0 0 0 0 0 0 0 0 BENZENE _1METHYL3PROPYL- 0 0 0 0 0 0 0 0 BENZENE _1ETHYL23DIMETHYL- 0 0 0 0 0 0 0 0 BENZENE _1245TETRAMETHYL- 0 19,526 0 0 1,953 17,573 17,573 19,526 BENZENE _1ETHYL24DIMETHYL- 0 0 0 0 0 0 0 0 BENZENE PROPYLBENZENE 0 0 0 0 0 0 0 0 M_CYMENE 0 0 0 0 0 0 0 0 SEC_BUTYLBENZENE 0 0 0 0 0 0 0 0 _1234TETRAMETHYL- 0 445 0 0 44 400 400 445 BENZENE _4ETHYL12DIMETHYL- 0 0 0 0 0 0 0 0 BENZENE P_XYLENE 5,563 0 0 0 0 0 0 5,569 NAPTHALENE 0 0 0 0 0 0 0 0 BUTYLBENZENE 0 0 0 0 0 0 0 0 _12DIETHYLBENZENE 0 0 0 0 0 0 0 0 _2METHYL1PROPYL- 0 0 0 0 0 0 0 0 BENZENE _1235TETRAMETHYL- 0 5,765 0 0 577 5,189 5,189 5,765 BENZENE PENTAMETHYLBENZENE 0 1,986 0 0 199 1,787 1,787 1,986 BICYCLOHEXYL 0 0 0 0 0 0 0 0 TOTAL LB/HR 30,430 75,335 507 21,528 5,381 48,427 48,427 106,272 ENTHALPY BTU/LB −88 −108 −1,034 −103 −105 −105 −111 −179 DENSITY LB/CUFT 52.91 45.44 0.08 46.07 44.93 44.93 45.27 51.57 VOLUMETRIC_FLOW GPM 72 207 795 58 15 134 133 257 STREAM NUMBER 20 99 100 TEMPERATURE DEG F. 331 328 380 PRESSURE PSIA 15 15 26 COMPONENTS MW HYDROGEN 0 0 0 METHANE 0 0 0 WATER 0 0 0 ETHANE 0 0 0 PROPANE 0 0 0 BUTANE 0 0 0 TOLUENE 0 0 0 BENZENE 0 0 0 O_XYLENE 92 92 0 _124TRIMETHYLBENZENE 7,142 474 6,668 _1ETHYL2METHYL- 0 0 0 BENZENE _1ETHYL4METHYL- 0 0 0 BENZENE _123TRIMETHYLBENZENE 2 0 2 _135TRIMETHYLBENZENE 14,291 14,068 223 M_XYLENE 1 1 0 _13DIETHYLBENZENE 0 0 0 _2ETHYL13DIMETHYL- 0 0 0 BENZENE _1METHYL3PROPYL- 0 0 0 BENZENE _1ETHYL23DIMETHYL- 0 0 0 BENZENE _1245TETRAMETHYL- 0 0 0 BENZENE _1ETHYL24DIMETHYL- 0 0 0 BENZENE PROPYLBENZENE 0 0 0 M_CYMENE 0 0 0 SEC_BUTYLBENZENE 0 0 0 _1234TETRAMETHYL- 0 0 0 BENZENE _4ETHYL12DIMETHYL- 0 0 0 BENZENE P_XYLENE 0 0 0 NAPTHALENE 0 0 0 BUTYLBENZENE 0 0 0 _12DIETHYLBENZENE 0 0 0 _2METHYL1PROPYL- 0 0 0 BENZENE _1235TETRAMETHYL- 0 0 0 BENZENE PENTAMETHYLBENZENE 0 0 0 BICYCLOHEXYL 0 0 0 TOTAL LB/HR 21,528 14,635 6,893 ENTHALPY BTU/LB −103 −106 −69 DENSITY LB/CUFT 46.07 45.90 44.86 VOLUMETRIC_FLOW GPM 58 40 19 STREAM NUMBER 16 38 48 53 54 73 TEMPERATURE DEG F. 95 148 101 101 101 77 PRESSURE PSIA 15 405 320 320 320 405 COMPONENTS MW HYDROGEN 3 6,281 5,803 5,803 0 478 METHANE 0 0 0 0 0 0 WATER 0 0 0 0 0 0 ETHANE 355 1,037 6,914 1,037 5,877 0 PROPANE 71 0 574 0 574 0 BUTANE 38 0 71 0 71 0 TOLUENE 15 0 48 0 48 0 BENZENE 0 0 0 0 0 0 O_XYLENE 4 0 15 0 15 0 _124TRIMETHYLBENZENE 0 0 31 0 31 0 _1ETHYL2METHYL- 0 0 0 0 0 0 BENZENE _1ETHYL4METHYL- 0 0 0 0 0 0 BENZENE _123TRIMETHYLBENZENE 0 0 1 0 1 0 _135TRIMETHYLBENZENE 0 0 16 0 16 0 M_XYLENE 15 0 52 0 52 0 _13DIETHYLBENZENE 0 0 0 0 0 0 _2ETHYL13DIMETHYL- 0 0 0 0 0 0 BENZENE _1METHYL3PROPYL- 0 0 0 0 0 0 BENZENE _1ETHYL23DIMETHYL- 0 0 0 0 0 0 BENZENE _1245TETRAMETHYL- 0 0 6 0 0 0 BENZENE _1ETHYL24DIMETHYL- 0 0 0 0 0 0 BENZENE PROPYLBENZENE 0 0 0 0 0 0 M_CYMENE 0 0 0 0 0 0 SEC_BUTYLBENZENE 0 0 0 0 0 0 _1234TETRAMETHYL- 0 0 0 0 0 0 BENZENE _4ETHYL12DIMETHYL- 0 0 0 0 0 0 BENZENE P_XYLENE 6 0 20 0 20 0 NAPTHALENE 0 0 0 0 0 0 BUTYLBENZENE 0 0 0 0 0 0 _12DIETHYLBENZENE 0 0 0 0 0 0 _2METHYL1PROPYL- 0 0 0 0 0 0 BENZENE _1235TETRAMETHYL- 0 0 1 0 1 0 BENZENE PENTAMETHYLBENZENE 0 0 0 0 0 0 BICYCLOHEXYL 0 0 0 0 0 0 TOTAL LB/HR 507 7,318 13,553 6,840 6,712 478 ENTHALPY BTU/LB −1,034 42 −618 −110 −1,139 0 DENSITY LB/CUFT 0.08 0.14 0.23 0.12 1.71 0.14 VOLUMETRIC_FLOW GPM 795 6,321 7,326 6,830 489 420 STREAM NUMBER 52 60 65 106 107 108 109 110 111 TEMPERATURE DEG F. 212 466 210 212 466 212 466 212 466 PRESSURE PSIA 500 495 15 500 495 500 495 500 495 COMPONENTS HYDROGEN LB/HR 0 0 0 0 0 0 0 0 0 METHANE LB/HR 0 0 0 0 0 0 0 0 0 WATER LB/HR 49,194 49,194 49,194 9,723 9,723 9,664 9,664 29,807 29,807 ETHANE LB/HR 0 0 0 0 0 0 0 0 0 PROPANE LB/HR 0 0 0 0 0 0 0 0 0 BUTANE LB/HR 0 0 0 0 0 0 0 0 0 TOLUENE LB/HR 0 0 0 0 0 0 0 0 0 BENZENE LB/HR 0 0 0 0 0 0 0 0 0 OXYGEN LB/HR 0 0 0 0 0 0 0 0 0 CARBON_ LB/HR 0 0 0 0 0 0 0 0 0 DIOXIDE NITROGEN LB/HR 0 0 0 0 0 0 0 0 0 PENTENE LB/HR 0 0 0 0 0 0 0 0 0 DICYCLO- LB/HR 0 0 0 0 0 0 0 0 0 PENTADIENE HEPTENE LB/HR 0 0 0 0 0 0 0 0 0 OCTANE LB/HR 0 0 0 0 0 0 0 0 0 OCTENE LB/HR 0 0 0 0 0 0 0 0 0 NONANE LB/HR 0 0 0 0 0 0 0 0 0 DECANE LB/HR 0 0 0 0 0 0 0 0 0 STYRENE LB/HR 0 0 0 0 0 0 0 0 0 TOTAL LB/HR 49,194 49,194 49,194 9,723 9,723 9,664 9,664 29,807 29,807 ENTHALPY BTU/LB −6,683 −5,593 −6,686 −6,683 −5,593 −6,683 −5,593 −6,683 5,593 DENSITY LB/ 57.31 0.09 57.40 57.31 0.90 57.31 0.90 57.31 0.90 CUFT VOLUMETRIC GPM 107 6,833 107 21 1,351 21 1,342 65 4,140 FLOW STREAM NUMBER 71 72 126 127 128 129 130 131 132 133 TEMPERATURE DEG F. 466 466 466 466 466 466 466 466 #N/A #N/A PRESSURE PSIA 495 495 495 495 495 495 495 495 #N/A #N/A COMPONENTS HYDROGEN LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A METHANE LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A WATER LB/HR 83,597 83,597 38,409 38,409 76,838 76,838 39,373 39,373 #N/A #N/A ETHANE LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A PROPANE LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A BUTANE LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A TOLUENE LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A BENZENE LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A OXYGEN LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A CARBON_ LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A DIOXIDE NITROGEN LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A PENTENE LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A DICYCLO- LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A PENTADIENE HEPTENE LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A OCTANE LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A OCTENE LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A NONANE LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A DECANE LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A STYRENE LB/HR 0 0 0 0 0 0 0 0 #N/A #N/A TOTAL LB/HR 83,597 83,597 38,409 38,409 76,838 76,838 39,373 39,373 #N/A #N/A ENTHALPY BTU/LB −5,593 −6,348 −5,593 −6,348 −5,593 −6,348 −5,593 −6,348 #N/A #N/A DENSITY LB/ 0.90 46.62 0.90 46.62 0.90 46.62 0.90 46.62 #N/A #N/A CUFT VOLUMETRIC_ GPM 11,612 224 535 103 10,673 295 5,469 105 #N/A #N/A FLOW STREAM NUMBER 66 68 106 107 108 109 TEMPERATURE DEG F. 88 108 212 466 212 466 PRESSURE PSIA 50 45 500 495 500 495 COMPONENTS HYDROGEN LB/HR 0 0 0 0 0 0 METHANE LB/HR 0 0 0 0 0 0 WATER LB/HR 1,170,770 1,170,770 9,723 9,723 9,664 9,664 ETHANE LB/HR 0 0 0 0 0 0 PROPANE LB/HR 0 0 0 0 0 0 BUTANE LB/HR 0 0 0 0 0 0 TOLUENE LB/HR 0 0 0 0 0 0 BENZENE LB/HR 0 0 0 0 0 0 OXYGEN LB/HR 0 0 0 0 0 0 CARBON_ LB/HR 0 0 0 0 0 0 DIOXIDE NITROGEN LB/HR 0 0 0 0 0 0 PENTENE LB/HR 0 0 0 0 0 0 DICYCLO- LB/HR 0 0 0 0 0 0 PENTADIENE HEPTENE LB/HR 0 0 0 0 0 0 OCTANE LB/HR 0 0 0 0 0 0 OCTENE LB/HR 0 0 0 0 0 0 NONANE LB/HR 0 0 0 0 0 0 DECANE LB/HR 0 0 0 0 0 0 STYRENE LB/HR 0 0 0 0 0 0 TOTAL LB/HR 1,170,770 1,170,770 9,723 9,723 9,664 9,664 ENTHALPY BTU/LB −6,807 −6,789 −6,683 −5,593 −6,683 −5,593 DENSITY LB/ 61.68 61.00 57.31 0.90 57.31 0.90 CUFT VOLUMETRIC_ GPM 2,366 2,393 21 1,351 21 1,342 FLOW STREAM NUMBER 75 76 85 92 93 98 103 104 914 TEMPERATURE DEG F. 105 140 140 105 140 105 105 140 128 PRESSURE PSIA 15 14 14 15 14 15 15 14 17 COMPONENTS HYDROGEN LB/HR 0 0 0 0 0 0 0 0 0 METHANE LB/HR 0 0 0 0 0 0 0 0 0 WATER LB/HR 0 0 0 0 0 0 0 0 0 ETHANE LB/HR 0 0 0 0 0 0 0 0 0 PROPANE LB/HR 0 0 0 0 0 0 0 0 0 BUTANE LB/HR 0 0 0 0 0 0 0 0 0 TOLUENE LB/HR 0 0 0 0 0 0 0 0 0 BENZENE LB/HR 0 0 0 0 0 0 0 0 0 OXYGEN LB/HR 60,131 374,661 60,131 1,430,390 1,430,390 374,661 712,871 712,871 7,113 CARBON_ LB/HR 0 0 0 0 0 0 0 0 0 DIOXIDE NITROGEN LB/HR 226,205 1,409,440 226,205 5,381,000 5,381,000 1,409,440 2,681,750 2,681,750 23,425 PENTENE LB/HR 0 0 0 0 0 0 0 0 0 DICYCLO- LB/HR 0 0 0 0 0 0 0 0 0 PENTADIENE HEPTENE LB/HR 0 0 0 0 0 0 0 0 0 OCTANE LB/HR 0 0 0 0 0 0 0 0 0 OCTENE LB/HR 0 0 0 0 0 0 0 0 0 NONANE LB/HR 0 0 0 0 0 0 0 0 0 DECANE LB/HR 0 0 0 0 0 0 0 0 0 STYRENE LB/HR 0 0 0 0 0 0 0 0 0 TOTAL LB/HR 286,336 1,784,100 286,336 6,811,300 6,811,300 1,784,100 3,394,620 3,394,620 30,538 ENTHALPY BTU/LB −7 15 15 7 15 7 7 15 12 DENSITY LB/ 0.07 0.06 0.06 0.07 0.06 0.07 0.07 0.06 0.08 CUFT VOLUMETRIC_ GPM 511,580 3,470,420 556,977 12,169,500 13,249,400 3,187,550 6,064,980 6,603,180 50,391 FLOW STREAM NUMBER 912 TEMPERATURE DEG F. 104 PRESSURE PSIA 115 COMPONENTS HYDROGEN LB/HR 0 METHANE LB/HR 1,404 WATER LB/HR 0 ETHANE LB/HR 42 PROPANE LB/HR 31 BUTANE LB/HR 0 TOLUENE LB/HR 0 BENZENE LB/HR 0 OXYGEN LB/HR 1 CARBON_DIOXIDE LB/HR 61 NITROGEN LB/HR 45 PENTENE LB/HR 0 DICYCLOPENTADIENE LB/HR 0 HEPTENE LB/HR 0 OCTANE LB/HR 0 OCTENE LB/HR 0 NONANE LB/HR 0 DECANE LB/HR 0 STYRENE LB/HR 0 TOTAL LB/HR 1,585 ENTHALPY BTU/LB −1,955 DENSITY LB/CUFT 0.32 VOLUMETRIC_FLOW GPM 609

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only exemplary embodiments have been shown and described. All changes, equivalents, and modifications that come within the spirit of the inventions defined by the following claims are desired to be protected. All publications, patents, and patent applications cited in this specification are herein incorporated by reference as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference and set forth in its entirety herein. 

The invention claimed is:
 1. A method for the production of mesitylene from an aromatic composition comprising aromatic components including methyl benzenes and C₂ and/or higher alkyl benzenes, including ethyl toluene, comprising: a. hydrodealkylating the aromatic components to convert the ethyl toluene to ethane and toluene and to convert the C₂ and/or higher alkyl benzenes to the corresponding alkanes and dealkylated aromatics while retaining the methyl benzenes; b. transalkylating the methyl benzenes to redistribute the methyl groups among the methyl benzenes to form trimethylbenzenes and other methylated benzenes; c. isomerizing the trimethylbenzenes to increase the amount of mesitylene in the aromatic composition; and d. recovering by distillation a TMB-rich product from the aromatic composition.
 2. The method of claim 1 in which said hydrodealkylating is performed in the presence of a suitable hydrodealkylating catalyst, and the transalkylating is performed in the presence of a suitable transalkylating catalyst.
 3. The method of claim 1 and which further includes combining elemental hydrogen with the feed stream for hydrodealkylating.
 4. The method of claim 3 further includes combining one or more of nitrogen, methane, ethane and propane with the feed stream for hydrodealkylating.
 5. The method of claim 1 which includes removing elemental hydrogen, methane, ethane and propane from the dealkylated product and recycling the elemental hydrogen to combine with the feed stream for hydrodealkylating.
 6. The method of claim 5 which removed methane is also recycled to combine with the feed stream for hydrodealkylating.
 7. The method of claim 1 which further includes introducing into the feed stream supplemental methylated aromatics.
 8. The method of claim 7 includes recovering C10 and higher aromatics and recycling them to the feed stream.
 9. The method of claim 8 which said recovering C10 and higher aromatics comprises recovering them from the isomerized product.
 10. The method of claim 1 which further includes combining supplemental methylated aromatics with the dealkylated product.
 11. The method of claim 10 which includes recovering C10 and higher aromatics and recycling them for combining with the dealkylated product for said transalkylating.
 12. The method of claim 11 in which said recovering C10 and higher aromatics comprises recovering them from the isomerized product.
 13. The method of claim 1 in which said hydrodealkylating and said transalkylating are performed together.
 14. The method of claim 1 in which said transalkylating and said isomerizing are performed together separate from said hydrodealkylating.
 15. The method of claim 14 in which said hydrodealkylating and said transalkylating/isomerizing are performed at different temperatures.
 16. The method of claim 1 in which said hydrodealkylating and said transalkylating are performed separately and at different temperatures.
 17. The method of claim 1 and which further includes processing the dealkylated product prior to said isomerizing to recover benzene, toluene and xylene.
 18. The method of claim 1 and which further includes processing the isomerized product to recover benzene, toluene and xylene.
 19. The method of claim 18 in which said processing the isomerized product comprises processing by distillation.
 20. The method of claim 19 in which said processing by distillation provides a BTX component and a TMB component, and in which said recovering a TMB-rich product comprises distilling the TMB component.
 21. The method of claim 20 which said recovering a TMB-rich product by distillation provides a C9 depleted component which is recycled to combine with the feed stream.
 22. The method of claim 20 in which said recovering a TMB-rich product by distillation provides a C9 depleted component which is recycled to combine with the dealkylated product for said transalkylating.
 23. The method of claim 22 which includes removing elemental hydrogen, methane, ethane and propane from the dealkylated product and recycling removed elemental hydrogen to combine with the feed stream for said hydrodealkylating.
 24. A method for the production of mesitylene-containing products from a feed stream comprising C₉ aromatic components, comprising: a. hydrodealkylating the feed stream to a dealkylated product having C2 and higher alkyl groups including ethyl toluene substantially removed from the aromatic components of the feed stream as their corresponding alkanes; b. transalkylating the dealkylated product to a transalkylated product having the distribution of methyl groups among the aromatic components of the dealkylated product rearranged; c. isomerizing the transalkylated product to increase the amount of mesitylene in the resulting isomerized product; d. processing the isomerized product to recover benzene, toluene and xylene, said processing the isomerized product comprising processing by distillation, said processing by distillation providing a BTX component and a TMB component; e. recovering a TMB-rich product from the isomerized product, said recovering a TMB-rich product comprising distilling the TMB component, said recovering a TMB-rich product by distillation providing a C9 depleted component; and f. recycling the C9 depleted component to combine it with the dealkylated product for said transalkylating, the C9 depleted component being combined with the dealkylated product to provide a methyl to benzene ratio of about 3.0.
 25. The method of claim 24 which includes removing elemental hydrogen, methane, ethane and propane from the dealkylated product and recycling removed elemental hydrogen to combine with the feed stream for said hydrodealkylating.
 26. The method of claim 1 in which the aromatic components include C7, C8, C9 and C10 alkyl benzenes, and in which said hydrodealkylating yields aromatic components including mono-, di-, tri- and tetra-methyl benzenes, said transalkylating redistributing the methyl groups among the mono-, di-, tri- and tetra methylbenzenes.
 27. The method of claim 26 in which the recovered TMB-rich product is treated to prepare a substantially-pure mesitylene product.
 28. The method of claim 26 in which said recovering a TMB-rich product is by distillation.
 29. The method of claim 28 which the recovered TMB-rich product is treated to prepare a substantially-pure mesitylene product.
 30. The method of claim 28 in which said recovering by distillation produces a bottom component including tetramethylbenzene, and in which bottom component including is recycled prior to said transalkylating.
 31. The method of claim 27 in which said hydrodealkylating and said transalkylating are performed separately and at different temperatures.
 32. The method of claim 26 in which recovered TMB-rich product is treated to prepare a substantially pure mesitylene product.
 33. The method of claim 28 which the feed stream includes lower paraffins, which method further including hydrocracking the paraffins. 